The present invention relates to programmable amplifiers with hysteresis, and more particularly, to amplifiers with that can be programmed to have positive and negative hysteretic threshold voltages.
Integrated circuits often have input buffers that receive input signals and drive signals to other parts of the integrated circuit. A differential input buffer senses differential input signals, converts the input signals to digital logic, and drives internal and external signals appropriately. One type of differential input buffer can drive input voltages that are generated according to the Low Voltage Differential Signal (LVDS) and Lightning Data Transport (LDT) differential input standards. To support other types of input voltage standards, extra circuitry and control RAM bits need to be added to this type of input buffer.
It would therefore be desirable to provide an input buffer that can support numerous differential input standards without the need for external components or additional internal circuitry. It would also be desirable to provide an input buffer that can sense a wider range of differential input voltages and common mode voltage levels than prior art input buffers. It would also be desirable to provide an input buffer that can be fabricated according to a wide range of semiconductor processes and that can operate within a wide range of supply voltages. It would also be desirable to provide an input buffer with these features and that can be easily maintained at a 50% duty cycle.